CN107843886B - Non-mechanical scanning laser radar optical device and laser radar system - Google Patents

Abstract

The invention discloses a non-mechanical scanning laser radar optical device and a laser radar system, wherein the device comprises a laser transmitting unit, a transmitting MEMS galvanometer, an MEMS galvanometer driving unit, a negative lens, a receiving MEMS galvanometer array and an optical receiving unit; the laser emitted by the laser emission unit is incident to the emission MEMS galvanometer, and the laser emitted by the emission MEMS galvanometer scans the object to be detected through the negative lens; the receiving MEMS galvanometer array receives the laser which is diffusely reflected on the tested object and reflects the received laser to the optical receiving unit; the MEMS galvanometer driving unit is used for adjusting the deflection angle of the transmitting MEMS galvanometer and adjusting the deflection angle of each MEMS galvanometer in the receiving MEMS galvanometer array. Compared with a device for realizing laser scanning by adopting motor drive, the MEMS galvanometer in the device has the advantages that the stability of the scanning laser radar optical device is improved, the service life is prolonged, the structure is simplified, and the size is reduced.

Description

A non-mechanical scanning lidar optical device and lidar system

Technical field

The invention belongs to the field of laser radar, and in particular relates to a non-mechanical scanning laser radar optical device and a laser radar system.

Background technique

With the continuous development of laser technology, the demand for high-frequency sweep, long-distance, high-precision, and small-volume lidar continues to increase, which poses new requirements and challenges to the laser field and related cooperation fields. Lidar has strict requirements on the stability and spatial size of its core optical system. The stability will seriously affect the ranging accuracy and service life of the lidar. If the spatial size is too large, the overall size of the lidar will be too large. Easy to integrate with other systems. Improving the stability of the optical system and reducing the spatial size can improve the stability and service life of the lidar system to a certain extent, and is conducive to the integrated use of lidar and other systems.

However, the structure of the currently commonly used mechanical scanning lidar optical system is relatively complex. At the same time, the mechanical scanning structure will also reduce the system stability and service life, and increase the system space size.

Contents of the invention

The technical problem to be solved by the present invention is how to improve the system stability of the scanning laser radar optical device, simplify the structure, and extend the service life.

In response to the above technical problems, the present invention provides a non-mechanical scanning lidar optical device, including a laser transmitting unit, a transmitting MEMS galvanometer, a MEMS galvanometer drive unit, a negative lens, a receiving MEMS galvanometer array and an optical receiving unit;

The laser emitted by the laser emitting unit is incident on the emitting MEMS galvanometer, and the laser emitted by the emitting MEMS galvanometer scans the object under test through the negative lens;

The receiving MEMS galvanometer array receives the laser light that is diffusely reflected on the object to be measured, and reflects the received laser light to the optical receiving unit;

The MEMS galvanometer driving unit is used to adjust the deflection angle of the transmitting MEMS galvanometer and adjust the deflection angle of each MEMS galvanometer in the receiving MEMS galvanometer array.

Preferably, the MEMS galvanometer driving unit is used to drive each MEMS galvanometer in the transmitting MEMS galvanometer and the receiving MEMS galvanometer array to vibrate in two mutually perpendicular directions.

Preferably, the laser emitting unit includes a laser generator and a beam shaping lens group;

The laser generator coincides with the main optical axis of the beam shaping lens group.

Preferably, the laser generator includes a laser driving component and a laser emitting component, and the laser driving component is used to modulate the laser light emitted from the laser emitting component.

Preferably, the beam shaping lens group is composed of at least one free-form surface lens or at least two ordinary lenses, and is used to shape the incident laser light.

Preferably, the optical receiving unit includes a receiving optical lens group and a photodetector;

The main optical axes of the receiving MEMS galvanometer array, the receiving optical lens group and the photodetector are coincident.

Preferably, the receiving optical lens group is composed of at least two groups of lenses for converging the laser light reflected from the receiving MEMS galvanometer array onto the photodetector.

Preferably, the projected area of the receiving MEMS galvanometer array in the main optical axis direction is greater than or equal to the effective aperture of the receiving optical lens group, and the vibration direction of the MEMS galvanometer in the receiving MEMS galvanometer array is determined according to the The vibration direction of the transmitting MEMS galvanometer is adjusted.

Preferably, the beam shaping lens group, the negative lens and the receiving optical lens group are all made of materials with high transmittance for near-infrared light, and the negative lens is used to amplify the light reflected by the transmitting MEMS galvanometer. Laser scanning field of view.

On the other hand, the present invention also provides a lidar system, including the above-mentioned non-mechanical scanning lidar optical device.

The invention provides a non-mechanical scanning lidar optical device and a lidar system. The non-mechanical scanning lidar optical device changes the offset angle of the transmitting MEMS galvanometer through a MEMS galvanometer driving unit, thereby detecting the incident to the emitting MEMS. The laser on the galvanometer adjusts the scanning angle. At the same time, the MEMS galvanometer drive unit changes the offset angle of each galvanometer in the receiving MEMS galvanometer array, thereby reducing the receiving field of view of the optical receiving unit. Compared with devices that use motor-driven laser scanning, MEMS galvanometers improve the stability of scanning lidar optical devices and extend their service life. In addition, because the MEMS galvanometer realizes laser scanning by changing the incident angle of the laser, it simplifies the structure of the scanning lidar optical device and reduces the size.

Description of the drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a non-mechanical scanning lidar optical device provided by an embodiment of the present invention;

Figure 2 is a schematic structural diagram of the side where the laser emitting unit of the non-mechanical scanning lidar optical device is located according to an embodiment of the present invention;

Figure 3 is a schematic structural diagram of the side where the optical receiving unit of the non-mechanical scanning lidar optical device is located according to an embodiment of the present invention;

Reference signs: 101-laser emitting unit, 102-emitting MEMS galvanometer, 103-MEMS galvanometer drive unit, 104-negative lens, 105-receiving MEMS galvanometer array, 106-optical receiving unit, 107-object to be measured, 108-modulated laser, 1011-laser driving component, 1012-laser emission component, 1013-beam shaping lens group, 1061-receiving optical lens group, 1062-photodetector.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Figure 1 is a schematic structural diagram of the non-mechanical scanning laser radar optical device provided in this embodiment. Referring to Figure 1, the non-mechanical scanning lidar optical device includes a laser transmitting unit 101, a transmitting MEMS galvanometer 102, a MEMS galvanometer drive unit 103, a negative lens 104, a receiving MEMS galvanometer array 105 and an optical receiving unit 106;

The laser emitted by the laser emitting unit 101 is incident on the emitting MEMS galvanometer 102, and the laser emitted by the emitting MEMS galvanometer 102 scans the object 107 through the negative lens 104;

The receiving MEMS galvanometer array 105 receives the laser light that is diffusely reflected on the object 107, and reflects the received laser light to the optical receiving unit 106;

The MEMS galvanometer driving unit 103 is used to adjust the deflection angle of the transmitting MEMS galvanometer 102 and adjust the deflection angle of each MEMS galvanometer in the receiving MEMS galvanometer array 105 .

Among them, MEMS galvanometer refers to a mirror that can drive the deflection direction through a microelectromechanical system. The MEMS galvanometer uses electrostatic drive and capacitive feedback. The MEMS galvanometer consists of a mirror, a movable frame and an outer frame. Vertical comb drivers are distributed in each mechanism. The MEMS galvanometer can perform simple string vibration under an external driving signal. For example, the MEMS galvanometer can be synthesized into a Lissajous figure through simple harmonic vibration in two vertical directions, that is, the path of the laser beam scan follows the Lissajous figure.

It should be noted that the structure of the existing mechanical scanning lidar optical device adopts a motor-driven method to realize laser scanning of the object to be measured. Since the motor is easily affected by external influences during use, such as external impact, and the motor has a short service life and needs to be replaced frequently, making the traditional scanning lidar optical device system poor in stability and short in service life. On the other hand, in optical devices that use motors to drive laser scanning, due to the large size of the motor, the scanning lidar optical device is bulky and has a complex structure, making it difficult to assemble and integrate with other devices.

The non-mechanical scanning lidar optical device provided in this embodiment uses a MEMS galvanometer driving unit to change the offset angle of the emitting MEMS galvanometer, thereby adjusting the scanning angle of the laser incident on the emitting MEMS galvanometer. At the same time, the MEMS galvanometer drive unit changes the offset angle of each galvanometer in the receiving MEMS galvanometer array, thereby reducing the receiving field of view of the optical receiving unit. Compared with devices that use motor-driven laser scanning, MEMS galvanometers improve the stability of scanning lidar optical devices and extend their service life. In addition, because the MEMS galvanometer realizes laser scanning by changing the incident angle of the laser, it simplifies the structure of the scanning lidar optical device and reduces the size.

Specifically, the MEMS galvanometer driving unit is used to drive each MEMS galvanometer in the transmitting MEMS galvanometer and the receiving MEMS galvanometer array to vibrate in two mutually perpendicular directions.

The MEMS galvanometer driving unit can drive each MEMS galvanometer in the transmitting MEMS galvanometer and the receiving MEMS galvanometer array to vibrate in two directions simultaneously.

Further, as shown in Figure 2, the laser emitting unit includes a laser generator (laser driving component 1011 and laser emitting component 1012 in Figure 2) and a beam shaping lens group 1013;

The main optical axis of the laser generator and the beam shaping lens group 1013 coincides with each other.

Further, the laser generator includes a laser driving component 1011 and a laser emitting component 1012. The laser driving component 1011 is used to modulate the laser light emitted from the laser emitting component 1012.

The modulated laser is preliminarily shaped by the beam shaping mirror group 1013 and then angularly deflected by the transmitting MEMS galvanometer 102. The negative lens 104 expands the scanning field of view of the laser reflected by the transmitting MEMS galvanometer 102, and further performs on the laser. After shaping, the modulated laser 108 is obtained, and the modulated laser 108 performs laser scanning on the object to be measured.

Further, the beam shaping lens group is composed of at least one free-form surface lens or at least two ordinary lenses, and is used to shape the incident laser light.

Further, as shown in Figure 3, the optical receiving unit 106 includes a receiving optical lens group 1061 and a photodetector 1062;

The main optical axes of the receiving MEMS galvanometer array, the receiving optical lens group and the photodetector are coincident.

Among them, the photodetector 1062 is located on the focal plane of the receiving optical lens group 1061.

Further, the receiving optical lens group is composed of at least two groups of lenses, used to converge the laser light reflected from the receiving MEMS galvanometer array onto the photodetector.

Further, the projected area of the receiving MEMS galvanometer array in the main optical axis direction is greater than or equal to the effective aperture of the receiving optical lens group, and the vibration direction of the MEMS galvanometer in the receiving MEMS galvanometer array is determined according to the The vibration direction of the transmitting MEMS galvanometer is adjusted.

Wherein, the receiving MEMS galvanometer array consists of n×m MEMS galvanometers, where n≥2 and m≥2.

The vibration direction of each galvanometer unit in the receiving MEMS galvanometer array is adjusted according to the vibration direction of the transmitting MEMS galvanometer, and the diffusely reflected light on the surface of the measured object is reflected to the receiving unit through the receiving MEMS galvanometer array. The optical lens group reduces the receiving field of view angle of the receiving optical lens group by adjusting the reflection angle of each galvanometer unit, thereby simplifying the structure of the receiving lens group.

The receiving optical lens group is used to converge the light reflected by the receiving MEMS galvanometer array onto the photodetector.

The vibration direction of each MEMS galvanometer in the transmitting MEMS galvanometer and receiving MEMS galvanometer arrays is controlled by the MEMS galvanometer drive unit. The MEMS galvanometer drive unit adjusts the receiving MEMS galvanometer accordingly according to the vibration direction of the transmitting MEMS galvanometer. The vibration direction of the MEMS galvanometer.

Further, the beam shaping lens group, the negative lens and the receiving optical lens group are all made of materials with high transmittance for near-infrared light, and the negative lens is used to amplify the light reflected by the transmitting MEMS galvanometer. Laser scanning field of view.

The beam shaping lens group is used to preliminarily shape the laser light emitted by the laser emission unit, and the negative lens is used to further shape the incident laser light.

As a more specific embodiment, with reference to Figures 1, 2 and 3, it can be seen that the laser driving component 1011 modulates the laser emitting component 1012, and the laser emitting component 1012 emits the modulated beam 108. The modulated beam 108 is preliminarily shaped after passing through the beam shaping lens group 1013 . The initially shaped modulated beam 108 is incident on the transmitting MEMS galvanometer 102 at a certain angle. Driven by the MEMS galvanometer drive unit 103, the transmitting MEMS galvanometer 102 deflects, and the initially shaped modulated beam 108 deflects with the transmitting MEMS galvanometer 102 and enters the negative lens 104 at a certain incident angle. The negative lens 104 finally shapes the modulated beam 108 and further expands the deflection angle of the modulated beam 108 to scan the object 107 to be measured.

The MEMS galvanometer driving unit 103 drives the receiving MEMS galvanometer array 105 according to the scanning angle of the modulated beam 108 . The diffusely reflected light beams at different angles are reflected by the receiving MEMS galvanometer array 105 and enter the receiving optical lens group 1061. The receiving optical lens group 1061 converges the diffusely reflected light beam onto the photodetector 1062.

This non-mechanical scanning lidar optical device uses a non-mechanical scanning optical system to improve the stability and service life of the system. Compared with the traditional mechanical scanning lidar optical device driven by a motor, the device provided in this embodiment simplifies the optical structure, reduces the design difficulty of the optical system, and reduces the spatial size of the device.

On the other hand, this embodiment also provides a lidar system, including the non-mechanical scanning lidar optical device described in the above embodiment.

The lidar system provided in this embodiment includes the non-mechanical scanning lidar optical device in the above embodiment, which changes the offset angle of the transmitting MEMS galvanometer through the MEMS galvanometer driving unit, thereby detecting the incident to the transmitting MEMS vibrator. The laser on the mirror adjusts the scanning angle. At the same time, the MEMS galvanometer drive unit changes the offset angle of each galvanometer in the receiving MEMS galvanometer array, thereby reducing the receiving field of view of the optical receiving unit. Compared with devices that use motor-driven laser scanning, MEMS galvanometers improve the stability of scanning lidar optical devices and extend their service life. In addition, because the MEMS galvanometer realizes laser scanning by changing the incident angle of the laser, it simplifies the structure of the scanning lidar optical device and reduces the size.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. A non-mechanical scanning laser radar optical device, characterized in that it includes a laser transmitting unit, a transmitting MEMS galvanometer, a MEMS galvanometer drive unit, a negative lens, a receiving MEMS galvanometer array and an optical receiving unit; The laser emitted by the laser emitting unit is incident on the emitting MEMS galvanometer, and the laser emitted by the emitting MEMS galvanometer scans the object under test through the negative lens; The receiving MEMS galvanometer array receives the laser light that is diffusely reflected on the object to be measured, and reflects the received laser light to the optical receiving unit; The MEMS galvanometer driving unit is used to adjust the deflection angle of the transmitting MEMS galvanometer and adjust the deflection angle of each MEMS galvanometer in the receiving MEMS galvanometer array; The optical receiving unit includes a receiving optical lens group; The projected area of the receiving MEMS galvanometer array in the main optical axis direction is greater than or equal to the effective aperture of the receiving optical lens group, and the vibration direction of the MEMS galvanometer in the receiving MEMS galvanometer array is based on the transmitting MEMS The vibration direction of the galvanometer is adjusted. 2. The device according to claim 1, characterized in that the MEMS galvanometer driving unit is used to drive each MEMS galvanometer in the transmitting MEMS galvanometer and the receiving MEMS galvanometer array in two vibrate in mutually perpendicular directions. 3. The device according to claim 2, wherein the laser emitting unit includes a laser generator and a beam shaping lens group; The laser generator coincides with the main optical axis of the beam shaping lens group. 4. The device according to claim 3, wherein the laser generator includes a laser driving component and a laser emitting component, and the laser driving component is used to modulate the laser light emitted from the laser emitting component. 5. The device according to claim 4, wherein the beam shaping lens group is composed of at least one free-form lens or at least two ordinary lenses, and is used to shape the incident laser. 6. The device according to claim 5, wherein the optical receiving unit also has a photodetector; The main optical axes of the receiving MEMS galvanometer array, the receiving optical lens group and the photodetector are coincident. 7. The device according to claim 6, wherein the receiving optical lens group is composed of at least two groups of lenses for converging the laser light reflected from the receiving MEMS galvanometer array to the photoelectric detection on the device. 8. The device according to claim 3, wherein the beam shaping lens group, the negative lens and the receiving optical lens group are all made of materials with high transmittance for near-infrared light, so The negative lens is used to expand the scanning field of view of the laser reflected by the emitting MEMS galvanometer. 9. A lidar system, characterized by comprising the non-mechanical scanning lidar optical device according to any one of claims 1 to 8.